Generation of Optical Carrier Suppressed Signal for Radio-over-Fiber (RoF) System Using Dual-Drive MachZehnder Modulator (original) (raw)
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PERFORMANCE ANALYSIS OF MACH-ZEHNDER MODULATOR IN RADIO OVER FIBER SYSTEMS
Radio over Fiber (RoF) is a next generation wireless broadband Internet access technology. In Radio over Fiber system the radio signal is generated at the central station is modulated on to light and transmitted over optical fiber cable to various base stations. The base station has to convert the optical signal to an electrical signal, amplify and transmit it. Modulation of RF signal onto light is a key function of the system. Both direct and external modulations are employed in RoF systems. External modulators are preferred in high performance RoF systems due to many advantages. The Mach-Zehnder Modulator (MZM) is a versatile external modulator which makes it attractive for Radio over Fiber systems. By using different combinations of applied electric fields, the Mach-Zehnder modulator can be used to generate phase modulation, amplitude modulation, or a number of other modulation formats. Here both simulative and experimental study of Radio over Fiber (RoF) system employing the Mach Zehnder Modulator (MZM) as external modulator is done. The modulator performance in various configurations are analyzed in this paper.
Performance evaluation of radio-over-fibre systems using Mach-Zehnder modulator
This paper investigates the bit error rate (BER) performance of a radio-overfibre (RoF) system utilizing the binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK) at a radio frequency (RF) of 5 GHz. The RF signal is externally modulated using the Mach-Zehnder modulator (MZM). The effects of noise sources and channels for the RoF link at distances of 30, 60, 90, 120 and 200 km are investigated. We shown that the RoF system offers lower BER performance compared to the RF wireless communication system employing the same modulation schemes.
Performance Analysis of RoF link using Mach-Zehnder Modulator and its parameters
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In radio-over-fiber (ROF) systems, optical carrier is modulated by the electrical signal and thus, converts the electrical signal to optical domain. This leads to the generation of up-converted signal bands. Although modulation is a necessary process for the faithful transmission of a signal, but it also degrades the modulated signal by generating distorted sidebands which causes reduction in the dynamic range of the system. Dispersion originated from the transmission fiber and other optical devices also change the phase relationship between the optical carrier and the modulated sidebands. This causes degradation of the modulated signal due to power fading. Mach-Zehnder modulator (MZM) is the most preferred modulator used in RoF systems. The performance of RoF system depends upon various parameters of Mach-Zehnder modulator (MZM) like RF bias, bias voltage, extinction ratio and insertion loss. In this paper the behavior of Lithium Niobate (LiNbO3) MZM is studied on various bias and ...
—This paper addresses the effects of fiber chromatic dispersion and Mach-Zehnder modulator (MZM) non-linearity on Radio-Over-Fiber (RoF) transmissions. An external intensity modulation and direct-detection link model by using a push-pull-type MZM and a photodetector is presented. The cyclic variation of radio frequency (RF) signal amplitude was predicted by J. Maeda (2012), applying several approximations. In this paper, the performance of link was investigated and the Graf's Theorem was used to obtain an exact analytical expression that properly takes into account both the dispersion-induced fading and all harmonics of sidebands generated by the nonlinear response of optical modulator. Results of numerical simulations shows that our approach allows the analysis of the link with higher modulation indexes.
Annual IEEE India Conference (INDICON), 2012, 2012
Radio over Free Space Optics (RoFSO) and Radio over Fiber (RoF) are recent technologies in optical communication systems. Both these technologies require some form of external optical modulator in the transmitter side. The commonly used optical modulators are Mach-Zehnder modulator (MZM) and Electro absorption modulator (EAM). In this paper, we analyze the performance of both Mach-Zehnder modulator and Electro absorption modulator for Radio over Free Space Optical Communication systems and it is compared with Radio over Fiber systems. We also discuss about the choice of optical modulator based on the intensity of output light signal.
Journal of Lightwave Technology, 2000
A dual-electrode Mach-Zehnder modulator for modulating a single channel or multiple channels in wavelengthdivision multiplexing (WDM) radio-over-fiber systems has been studied and analyzed to determine the effect of bias shifting on the dynamic range (DR) of the modulator. A closed-form expression of a realistic DR as a function of systems' parameters and all main sources of noise at the receiver has been derived. The results of the study indicated that the derived computational expression is general and can be applied for a wide range of parametric variations.
Optical and Quantum Electronics, 2021
In this work, we presented a radio-over-fiber (ROF) access network through two modulation stages for the generation of multiple millimeter wave (mm-wave) signals with frequencies of 20GHz, 40GHz, 60GHz and 80 GHz for the transmission rate of 10 Gbps as a function of the variation of link distance and signal power. The specific purpose of the paper was to design and to investigate a RoF system based on the variation of mm-wave frequencies in order to implement a simple and effective system. In stage 1, there are two modulators in parallel (MZMa and MZMb) called dual-parallel Mach-Zehnder modulator (DP-MZM) and in stage 2 there is only one modulator (MZMc), connected to three pulse generators: Non-Return-to-Zero (NRZ), Return-to-Zero (RZ). A single-mode fiber (SMF) and Gaussian and an erbium-doped fiber amplifier (EDFA) were also used to send signals to base stations (BSs). The numerical analyzes of the results of the eye diagrams showed excellent bit error rate (BER) and quality factor (Q-factor) values, which proved the good performance of the proposed ROF DP-MZM system, for the three encoding formats used, which was able to generate 3-tupling mm-wave for multiple wireless accesses.
Simulations of modulator nonlinear effects in radio-over-fibre systems
Journal of Applied Mechanics-transactions of The Asme - J APPL MECH, 2007
We propose the use of optical frequency multiplication as a cost-effective method to optically generate wireless radio frequencies (RFs) and deliver them from a central station to remote radio access units. Mach-Zehnder modulators (MZMs) are employed to transport the RF data. We focus on the impact of the nonlinearity of MZMs on the radioover-fibre system performance for single-carrier and orthogonal frequency division multiplexing (OFDM) formatted data. A larger system penalty is shown in the OFDM RoF system due to a more severe nonlinear cross-talk effect between sub-carriers, compared with the single carrier system.
Optik, 2018
In this research paper, we report on a simulation study of the Radio over Fibre (RoF) Carrier Suppressed Single Sideband (CS-SSB) modulation scheme. This scheme is based on a Dual Parallel Dual Drive Mach-Zehnder modulator (DP-DDMZM), for a longdistance transmission. The proposed system consists of the combination of a carrier and a message signal at two parallel modulators, where the laser and link power is varied for the two different dispersion compensation techniques. We found that by suppressing the optical carrier and cancelling one sideband, we can limit the nonlinear effects that are caused by power fading and interference. We demonstrate that by varying the launched laser and link power up to optimised threshold levels, the signal to noise ratio (SNR) increases and the Q-Factor improves significantly. Our proposed RoF optic communication architecture can support an extended reach transmission of up to 200km without dispersion compensation. Moreover, for the bitrate of 10 Gbit/s and span length of 25 km, we achieved a span ratio of 520, alternatively viewed as the system link signal transmission distance of 13000 km. Therefore, this method is cost-effective and less complex.